1. Technical Field of the Invention
The present invention relates in general to video surveillance systems and in particular, to viewing digital video streams from video surveillance cameras.
2. Description of Related Art
Smartphones and other mobile devices having high-resolution touch screens and high-speed network access are becoming commonplace in the marketplace. Similarly, IP-video surveillance cameras and legacy analog surveillance cameras enabled with IP-encoders are now widely deployed on city streets, in airports, and in many other public facilities. Security companies have expressed interest in being able to view the surveillance camera streams in real-time on mobile devices coupled to the IP network. However, the small screen size of a typical mobile device currently makes viewing multiple video streams in parallel impractical.
One solution is to display the multiple video streams simultaneously, but with each having reduced window size and resolution. However, the smaller video window size can cause a human viewer to miss important or critical information. Another solution is to cycle or toggle between multiple video streams, so that only a single stream, or a few streams of the total set are displayed in full resolution at one time. For example, a typical video surveillance screen might show Camera-1 for the first 10 seconds, Camera-2 for the next 10 seconds, Camera-N for the next 10 seconds, etc. and then repeat back to Camera-1. However, critical activity happening within Camera-1's field-of-view may not be seen while Cameras 2-N are being viewed.
Digital video buffering is also commonly utilized in many digital video devices, such as personal video recorders (PVRs) and digital video recorders (DVRs). For example, in a conventional DVR system, a user can watch television (TV) in real-time, pause the video, and then continue watching the video in real-time but with a delay. The user could also watch the video at 2× or 4× the speed in order to catch-up with the real-time television show. In some DVR systems, a user might even be able to watch two channels of TV at the same time in this way, i.e., watching one channel for some time while the second channel is paused, then watching the second channel for some time while the first channel is paused. However, this process is manual and extremely cumbersome. As such, the human viewer may quickly fall-behind watching both TV shows. Moreover, this process would be nearly impossible for more than two channels of video.